A MultilinearHandler handles terms like $x_0x_1^2$ . More...

#include <MultilinearHandler.h>

Inheritance diagram for Minotaur::MultilinearHandler:

Collaboration diagram for Minotaur::MultilinearHandler:

[legend]

Public Member Functions
	MultilinearHandler (EnvPtr env, ProblemPtr problem)
	Default constructor.

virtual	~MultilinearHandler ()
	Destroy.

bool	findOriginalVariable (ConstVariablePtr rv, ConstVariablePtr &ov) const

virtual void	getBranchingCandidates (RelaxationPtr rel, const DoubleVector &x, ModVector &mods, BrVarCandSet &cands, BrCandVector &gencands, bool &is_inf)

bool	isFeasible (ConstSolutionPtr, RelaxationPtr, bool &should_prune, double &inf_meas)

void	relax (RelaxationPtr relaxation, bool &isInfeasible)

void	relaxInitFull (RelaxationPtr, bool *)

void	relaxInitInc (RelaxationPtr, bool *)

void	relaxNodeFull (NodePtr, RelaxationPtr, bool *)
	Create a relaxation for a node, building from scratch.

void	relaxNodeInc (NodePtr, RelaxationPtr, bool *)
	Create an incremental relaxation for a node.

void	relaxNode (NodePtr node, RelaxationPtr relaxation, bool &isInfeasible)

std::map< std::vector< ConstVariablePtr >, ConstVariablePtr >	getRevMlterms ()

std::map< ConstVariablePtr, std::vector< ConstVariablePtr > >	getMlterms ()

std::map< ConstVariablePtr, UInt >	getMaxPow ()

std::map< ConstVariablePtr, ConstVariablePair >	getBlterms ()

std::map< ConstVariablePair, ConstVariablePtr >	getRevBlterms ()

std::map< VarIntMap, ConstVariablePtr >	getMonomialterms ()

std::map< ConstVariablePtr, ConstVariablePair >	getSqterms ()

std::map< ConstVariablePair, ConstVariablePtr >	getRevSqterms ()

std::vector< std::vector< ConstVariablePtr > >	getGroups ()

std::vector< std::vector< ConstVariablePtr > >	getAllLambdas ()

std::map< ConstVariablePtr, ConstVariablePtr >	getOriginalVariablesMap ()

std::map< ConstVariablePtr, ConstVariablePtr >	getRevOriginalVariablesMap ()

std::map< ConstVariablePtr, std::vector< ConstVariablePtr > >	getNewCopyVariables ()

std::map< VarIntMap, ConstVariablePtr >	getMonomialTerms ()

std::map< ConstVariablePair, ConstVariablePtr >	getRevBilinearTerms ()

void	separate (ConstSolutionPtr, NodePtr, RelaxationPtr, CutManager , SolutionPoolPtr, bool , SeparationStatus *)
	Can not return any cuts for this case.

virtual ModificationPtr	getBrMod (BrCandPtr, DoubleVector &, RelaxationPtr, BranchDirection)
	Get the modifcation that creates a given (up or down) branch.

virtual Branches	getBranches (BrCandPtr cand, DoubleVector &x, RelaxationPtr rel, SolutionPoolPtr s_pool)
	Return branches for branching.

virtual SolveStatus	presolve (PreModQ , bool changed, Solution **)
	Initial presolve.

virtual bool	presolveNode (RelaxationPtr, NodePtr, SolutionPoolPtr, ModVector &, ModVector &)
	Presolve the problem and its relaxation at a node.

std::string	getName () const
	Return the name of the handler.

Public Member Functions inherited from Minotaur::Handler
	Handler ()
	Default constructor.

virtual	~Handler ()
	Destroy.

virtual void	addConstraint (ConstraintPtr newcon)
	Add constraint to be handled by this handler.

virtual ConstraintVector::const_iterator	consBegin () const

virtual ConstraintVector::const_iterator	consEnd () const

virtual int	fixNodeErr (RelaxationPtr, ConstSolutionPtr, SolutionPoolPtr, bool &)

bool	getStrongerMods (RelaxationPtr rel, NodePtr node, SolutionPoolPtr s_pool, ModVector &p_mods, ModVector &r_mods)
	do node presolve to get mods for stronger branching All params are presolveNode params.

virtual bool	isNeeded ()
	Return true if this handler is needed for the problem.

virtual bool	postSolveRootNode (RelaxationPtr, SolutionPoolPtr, ConstSolutionPtr, ModVector &, ModVector &)
	At the root node post solve the problem and its relaxation. LP based bound tightening (OBBT) is employed here after filtering variables for which no OBBT is required.

virtual void	relaxInitFull (RelaxationPtr rel, SolutionPool sp, bool is_inf)=0
	Create root relaxation if doing full node relaxations.

virtual void	relaxInitInc (RelaxationPtr rel, SolutionPool sp, bool is_inf)=0
	Create root relaxation if doing incremental node relaxations.

virtual void	removeCuts (RelaxationPtr, ConstSolutionPtr)

virtual void	separate (ConstSolutionPtr sol, NodePtr node, RelaxationPtr rel, CutManager cutman, SolutionPoolPtr s_pool, ModVector &p_mods, ModVector &r_mods, bool sol_found, SeparationStatus *status)=0
	add cuts to separate a given point.

virtual void	setModFlags (bool mod_prob, bool mod_rel)
	Tell the handler whether the problem will be modified or the relaxation will be modified or both. These modifications will be saved in the tree as well.

virtual void	simplePresolve (ProblemPtr, SolutionPoolPtr, ModVector &, SolveStatus &status)

void	undoStrongerMods (ProblemPtr p, RelaxationPtr rel, ModVector &p_mods, ModVector &r_mods)
	Undo Modifications made during stronger branching.

virtual void	writeStats (std::ostream &) const
	Write statistics to ostream out.

Protected Attributes
EnvPtr	env_
	Environment.

ConstProblemPtr	problem_

ProblemPtr	workingProblem_

Protected Attributes inherited from Minotaur::Handler
ConstraintVector	cons_

bool	modProb_
	If true, modify the original (or transformed) problem.

bool	modRel_
	If true, modify the relaxation of original (or transformed) problem.

Detailed Description

A MultilinearHandler handles terms like $x_0x_1^2$ .

Member Function Documentation

◆ getAllLambdas()

std::vector< std::vector< ConstVariablePtr > > Minotaur::MultilinearHandler::getAllLambdas ( )

inline

Return the lambda variables introduced for the Grouped Convex Hull relaxation

◆ getBlterms()

std::map< ConstVariablePtr, ConstVariablePair > Minotaur::MultilinearHandler::getBlterms ( )

inline

Retrun the blterms_

◆ getBranches()

Branches MultilinearHandler::getBranches	(	BrCandPtr	cand,
		DoubleVector &	x,
		RelaxationPtr	rel,
		SolutionPoolPtr	s_pool
	)

virtual

Return branches for branching.

Get branches by branching on the given candidate. In the general scheme for branching, we store only bound changes, though we are also capable of storing other mods.

Parameters

[in]	cand	Candidate on which the brancher wants to branch.
[in]	x	The solution of the relaxation at the current node.
[in]	rel	The relaxation at the current node.
[in]	s_pool	Best feasible solutions found so far.

Returns: a vector of branch-objects.

Implements Minotaur::Handler.

◆ getBranchingCandidates()

void MultilinearHandler::getBranchingCandidates	(	RelaxationPtr	rel,
		const DoubleVector &	x,
		ModVector &	mods,
		BrVarCandSet &	cands,
		BrCandVector &	gencands,
		bool &	is_inf
	)

virtual

Both $x_0, x_1$ are branching candidates. The McCormick inequalities must be updated after branching.

Implements Minotaur::Handler.

◆ getBrMod()

ModificationPtr MultilinearHandler::getBrMod	(	BrCandPtr	cand,
		DoubleVector &	x,
		RelaxationPtr	rel,
		BranchDirection	dir
	)

virtual

Get the modifcation that creates a given (up or down) branch.

If one branch is pruned by the brancher (e.g. strong brancher), then we can apply the modifications of other branch to the relaxation without branching. This routine returns such a modification. This function is also called for obtaining modifications for strong branching on a candidate.

Parameters

[in]	cand	The candidate for which we want the modification.
[in]	x	The solution of relaxation at current node.
[in]	rel	The relaxation at current node.
[in]	dir	The Direction for which we want the modification, Up or Down?.

Returns: Modification that can be applied to the relaxation before re-solving it.

Implements Minotaur::Handler.

◆ getGroups()

std::vector< std::vector< ConstVariablePtr > > Minotaur::MultilinearHandler::getGroups ( )

inline

Return the groups of variables that are made for the Grouped Convex Hull relaxation

◆ getMaxPow()

std::map< ConstVariablePtr, UInt > Minotaur::MultilinearHandler::getMaxPow ( )

inline

Retrun the max_pow_

◆ getMlterms()

std::map< ConstVariablePtr, std::vector< ConstVariablePtr > > Minotaur::MultilinearHandler::getMlterms ( )

inline

Return mlterms_

◆ getMonomialterms()

std::map< VarIntMap, ConstVariablePtr > Minotaur::MultilinearHandler::getMonomialterms ( )

inline

Retrun the monomial_terms__

◆ getMonomialTerms()

std::map< VarIntMap, ConstVariablePtr > Minotaur::MultilinearHandler::getMonomialTerms ( )

inline

Retrun the map of monomial terms

◆ getName()

std::string MultilinearHandler::getName ( ) const

virtual

Return the name of the handler.

Implements Minotaur::Handler.

◆ getNewCopyVariables()

std::map< ConstVariablePtr, std::vector< ConstVariablePtr > > Minotaur::MultilinearHandler::getNewCopyVariables ( )

inline

Return the map between the original variables and the copy variables for its exponents

◆ getOriginalVariablesMap()

std::map< ConstVariablePtr, ConstVariablePtr > Minotaur::MultilinearHandler::getOriginalVariablesMap ( )

inline

Return the map between the original variables and the variables in the relaxation

◆ getRevBilinearTerms()

std::map< ConstVariablePair, ConstVariablePtr > Minotaur::MultilinearHandler::getRevBilinearTerms ( )

inline

Return the map of bilinear terms (map of a variable pair and a substiture variable)

◆ getRevBlterms()

std::map< ConstVariablePair, ConstVariablePtr > Minotaur::MultilinearHandler::getRevBlterms ( )

inline

Retrun the rev_blterms_

◆ getRevMlterms()

std::map< std::vector< ConstVariablePtr >, ConstVariablePtr > Minotaur::MultilinearHandler::getRevMlterms ( )

inline

Return rev_mlterms_

◆ getRevOriginalVariablesMap()

std::map< ConstVariablePtr, ConstVariablePtr > Minotaur::MultilinearHandler::getRevOriginalVariablesMap ( )

inline

Return the REVERSE map between the original variables and the variables in the relaxation

◆ getRevSqterms()

std::map< ConstVariablePair, ConstVariablePtr > Minotaur::MultilinearHandler::getRevSqterms ( )

inline

Retrun the rev_sqterms_

◆ getSqterms()

std::map< ConstVariablePtr, ConstVariablePair > Minotaur::MultilinearHandler::getSqterms ( )

inline

Retrun the sqterms_

◆ isFeasible()

bool MultilinearHandler::isFeasible	(	ConstSolutionPtr	,
		RelaxationPtr	,
		bool &	should_prune,
		double &	inf_meas
	)

virtual

Check if each multilinear constraint is satisfied. Stops on the first violated constraint.

Implements Minotaur::Handler.

◆ presolve()

virtual SolveStatus Minotaur::MultilinearHandler::presolve	(	PreModQ *	pre_mods,
		bool *	changed,
		Solution **	sol
	)

inlinevirtual

Initial presolve.

Do the initial presolve. For now we will assume that presolve modifies the given problem. We do not create a new problem. All modifications that require post-processing for getting the solution back are prepended to 'pre_mods' by the handler.

Parameters

[in]	pre_mods	A pointer to a queue of PreMod objects. Modifications made by the presolver must be prepended (not appended) to pre_mods. The order is important for post-solve.
[out]	changed	True if the presolve modified the problem.

Returns: status of presolve.

Parameters

[out] sol Optimal solution found by the handler, if any. The status must be SolvedOptimal if and only if sol is created.

Implements Minotaur::Handler.

◆ presolveNode()

virtual bool Minotaur::MultilinearHandler::presolveNode	(	RelaxationPtr	rel,
		NodePtr	node,
		SolutionPoolPtr	s_pool,
		ModVector &	p_mods,
		ModVector &	r_mods
	)

inlinevirtual

Presolve the problem and its relaxation at a node.

Presolve the problem and its relaxation at a given node. Bound propagation and other simple modifications can be made in this function. It is called after the node relaxation is setup but before it is solved. Both the problem and its relaxation are presolved. Changes to the problem are stored in the tree. Changes to the relaxation are optional and may or may not be stored in the tree.

Parameters

[in]	rel	Relaxation at the current node.
[in]	node	Current node.
[in]	s_pool	Pool of solutions.
[in]	p_mods	Unused. Modifications to the problem that must be stored in this node so that they are applied to all descendant nodes as well. All modifications must be appended not prepended.
[out]	r_mods	Modifications to the relaxation that must be stored in this node so that they are applied to all descendant nodes as well. All modifications must be appended not prepended. This may be unnecessary in certain algorithms.

Returns: true if Node can be pruned because infeasibility is detected.

Implements Minotaur::Handler.

◆ relaxNodeFull()

void Minotaur::MultilinearHandler::relaxNodeFull	(	NodePtr	node,
		RelaxationPtr	rel,
		bool *	is_inf
	)

inlinevirtual

Create a relaxation for a node, building from scratch.

Create a relaxation of the constraints. Either this method, or relaxNodeInc should be called at each node. Here, we only make minor modifications to the same relaxation.

Parameters

[in]	node	is the node for which relaxation is to be created.
[in]	rel	is the relaxation that is being constructed. Do not allocate or re-allocate space for it. Just add new variables or constraints to it.
[out]	is_inf	is true if the node can be pruned.

Implements Minotaur::Handler.

◆ relaxNodeInc()

void Minotaur::MultilinearHandler::relaxNodeInc	(	NodePtr	node,
		RelaxationPtr	rel,
		bool *	is_inf
	)

inlinevirtual

Create an incremental relaxation for a node.

Create a relaxation of the constraints. Either this method, or nodeRelaxFull relax should be called at root node. Usually we only make minor modifications to the same relaxation.

Parameters

[in]	node	is the node for which relaxation is to be created.
[in]	rel	is the relaxation that is being constructed. Do not allocate or re-allocate space for it. Just add new variables or constraints to it.
[out]	is_inf	is true if the node can be pruned.

Implements Minotaur::Handler.

The documentation for this class was generated from the following files:

/home/amahajan/tmp/minotaur-test/src/base/MultilinearHandler.h
/home/amahajan/tmp/minotaur-test/src/base/MultilinearHandler.cpp

Public Member Functions

Protected Attributes

Detailed Description

Member Function Documentation

◆ getAllLambdas()

◆ getBlterms()

◆ getBranches()

◆ getBranchingCandidates()

◆ getBrMod()

◆ getGroups()

◆ getMaxPow()

◆ getMlterms()

◆ getMonomialterms()

◆ getMonomialTerms()

◆ getName()

◆ getNewCopyVariables()

◆ getOriginalVariablesMap()

◆ getRevBilinearTerms()

◆ getRevBlterms()

◆ getRevMlterms()

◆ getRevOriginalVariablesMap()

◆ getRevSqterms()

◆ getSqterms()

◆ isFeasible()

◆ presolve()

◆ presolveNode()

◆ relaxNodeFull()

◆ relaxNodeInc()